Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user. Updates are available.
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
This vulnerability exists due to errors in parsing index values within malformed formulas contained in Excel documents. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious file. If the user views the file, the attacker could execute arbitrary code on the system with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Office Excel 2002 SP3 and prior
Office Excel 2003 SP3 and prior
Office Excel 2007 SP2 and prior
Office Excel Viewer 2003 SP3 and prior
Office Excel Viewer 2007 SP2 and prior
Office 2004 for Mac
Office 2008 for Mac
Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 and prior
An attacker cannot directly exploit this vulnerability, and instead must convince a user to participate in an attack by viewing a malicious document. Attackers may deliver files to users as e-mail attachments or posted on public websites, and attackers may use social engineering techniques in an attempt to convince users to open a provided document.
Systems most at risk are end-user hosts on which users run applications with elevated privileges, as any code execution as the result of an exploit may also run with elevated privileges, possibly resulting in a complete compromise. Systems that restrict user privileges may have less risk in the event of an exploit because any executed code would run in a limited security context, affecting only user files.
Microsoft has released a security bulletin at the following link: MS09-067
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If that user holds elevated privileges, the attacker could execute arbitrary code resulting in a complete system compromise.
This vulnerability exists due to errors in parsing index values within malformed formulas contained in Excel documents. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious Excel file. When opened and processed, the document could trigger memory corruption that the attacker could leverage to execute arbitrary code with the privileges of the user.
Administrators are advised to apply the available software updates.
Users are advised not to open unsolicited e-mail attachments. Users should verify that attachments are safe before opening them.
Users are advised to run applications with the least privileges possible.
Users may consider applying the Microsoft Office Isolated Conversion Environment (MOICE) to safely open Excel files from suspicious or unrecognized sources on systems that are running Microsoft Office 2003 or Office 2007.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
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